This invention relates to food thawing apparatus and method and, more particularly, to apparatus and method adapted for incorporation in a household refrigerator which operates to thaw frozen food and maintain the thawed food at refrigerated temperatures.
The advantages of freezing food for preservation purposes are offset to some extent by the need to thaw the frozen food before it can be made ready for food preparation. In general, the need to thaw certain foods before cooking or making use of it in food preparation procedures is well known. Typically, thawing of frozen food can be accomplished by allowing the food to stand at room temperature until it is fully thawed. Such thawing, however, results in a substantial amount of liquid being drained from the food. In addition, when the food is allowed to stand at room temperature, the timing must be such that the food is used promptly upon thawing or else placed back into the refrigerator to avoid the possibility of food spoilage. In some cases, it is recommended that the frozen food be placed in the fresh food compartment of a refrigerator until thawed. This procedure, however, takes a very long time to achieve thawing.
Microwave ovens are currently available that have provision for a low-power setting intended to permit thawing of frozen food by means of electromagnetic radiation of energy into the food load. Although somewhat beneficial for this purpose, the microwave oven has certain drawbacks when used for defrosting frozen food. One of the drawbacks is that the frozen food is heated initially near the surface of the food load with internal heating (thawing) being a function of the degree of heat conduction through the food from the surface. Moreover, energy load-in at localized portions of the food, e.g., in the vicinity of a bone, can actually cause the food to become fully cooked at these locations while other portions of the food load are still frozen. In addition, once the food load is thawed, it either must be used immediately or placed back in the refrigerator to again avoid the possibility of food spoilage.
In the past, refrigerators have been provided with a frozen food thawing compartment that is located adjacent to the machine compartment so that air heated by the machine compartment, such as the condensing unit, flows into the receptacle to warm the frozen food articles and thaw them. See, for example, U.S. Pat. Nos. 2,465,107; 2,467,464; and 2,758,452. This type of refrigerator thawing does not avoid the possibility of food spoilage once the food is thawed and, in fact, may promote spoilage because of the elevated temperature unless it is used immediately or placed in the refrigerator compartment for preservation.
Refrigerators have also been provided with compartments for thawing frozen food which compartments are insulated and heated by a hot gas circuit in the refrigerating system. See, for example U.S. Pat. No. 3,134,242. This type of food thawing system in refrigerators requires that a substantial amount of heat be applied in one form or another to the food items being thawed. In a refrigerating atmosphere, this is not desirable from an energy saving standpoint as the refrigerator must work harder in order to maintain the proper refrigerated temperature within the refrigerator and the thawing chamber must be heavily insulated. Moreover, when the food is thawed, it is maintained at an elevated temperature that again could cause spoilage unless removed from the thawing chamber and placed in the refrigerated compartment.
There is, therefore, a need for a reliable, low cost, food thawing apparatus and method suitable for household use. There is a need for such an apparatus and method that does not require constant attendance to avoid food spoilage and for an apparatus and method that uniformly thaws the food load without heating of the food load before complete thawing is achieved. By my invention, there is provided an apparatus and method for thawing frozen food which will accomplish the above-desired results and which is easy to utilize for its intended purpose.